Phase II Study of Neoadjuvant Anthracycline-Based Regimens Combined With Nanoparticle Albumin-Bound Paclitaxel and Trastuzumab for Human Epidermal Growth Factor Receptor 2-Positive Operable Breast Cancer

IntroductionNeoadjuvant chemotherapy plus trastuzumab results in a 30% to 50% pathologic complete response (pCR) rate in human epidermal growth factor receptor 2 (HER2)-positive breast cancer and has been associated with improved therapeutic outcomes. Thus, the pCR rate can be useful in evaluating novel agents in this patient population. Nanoparticle albumin-bound (nab)-paclitaxel (PTX) can reduce the toxicity of PTX while maintaining its efficacy. The present study evaluated the activity and safety of nab-PTX as a neoadjuvant treatment of HER2+ breast cancer.Patients and MethodsWe treated patients with stage I to IIIA breast cancer using neoadjuvant epirubicin/cyclophosphamide (EC) or 5-fluorouracil/epirubicin/cyclophosphamide every 3 weeks (q3w) for 4 cycles, followed by nab-PTX (260 mg/m2) plus trastuzumab q3w for 4 cycles. The primary endpoint was the pCR rate. The secondary endpoints included the clinical response rate, disease-free survival, pathologic response rate (defined as pCR or minimal residual invasive disease only in the breast), breast-conserving surgery rate, and safety.ResultsForty-six patients were enrolled. One patient met the exclusion criteria because of the coexistence of another malignant disease; therefore, we evaluated 45 patients in the entire study. One patient experienced rapid disease progression during EC therapy, leaving 44 patients evaluable for nab-PTX treatment. Of the 45 patients, 49% achieved a pCR. The pCR rate was 36% and 71% in those with estrogen receptor-positive and -negative cancer, respectively. Of all the study treatments, the most frequent reason for delay or dose reduction was hematologic toxicity; only 1 patient required a dose reduction for nab-PTX because of peripheral neuropathy.ConclusionNeoadjuvant therapy using this combination appears to be effective and safe.